Fig. 1 Size fractions of MPPs in different fertilizers. Size fractions of MPPs in different fertilizers. Digests A/B/C/D, biowaste digester; EC, energy crop digester; CP 8 mm/15 mm, biowaste composting plant. Nicolas Weithmann et al. Sci Adv 2018;4:eaap8060 Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).